1. Field of the Invention
The present invention relates to a small-sized and good heat efficiency brazing system which is suitable for brazing automobile heat exchangers and other various types of metal products, in particular for individually brazing workpieces.
2. Description of the Related Art
An automobile heat exchanger is produced by assembling aluminum components and joining them by a brazing material. As a conventional brazing system which is used for the brazing process, one which is provided with a large-sized continuous oven which conveys a plurality of workpieces by a conveyor and consecutively brazes them is known (for example, Japanese Patent Publication (A) No. 2007-78328 etc.) One example of the hardware configuration is shown in FIG. 12A and FIG. 12B. In FIG. 12A, at one end side of a brazing chamber 102, a preheating chamber 101 is connected via a passage 103. At the other end side of the brazing chamber 102, a cooling chamber 104 which is comprised of a slow cooling chamber 105 and a rapid cooling chamber 106 is arranged. A heating passage 107 is formed connecting the insides of these chambers (FIG. 12B). The preheating chamber 101 has an open part 100 at one end side and is communicated through the heating passage 107 with an open part 108 which is formed at the other end side of the rapid cooling chamber 106.
As shown in FIG. 12B, the heating passage 107 is loaded with workpieces W carried on a conveyor 109 from the open part 100 of the preheating chamber 101. The inside of the preheating chamber 101 is an air atmosphere. At the top surface, an in-oven circulating fan F′ is set. Due to the heat sources H′ (gas or electric heaters etc.) which are arranged above and below the conveyor 109, for example, the temperature is controlled to 400° C. and the workpieces W′ on the conveyor 109 are preheated. The following brazing chamber 102 similarly has an in-oven circulating fan F′ at its top surface. The inside of the oven is made a nitrogen atmosphere so as to maintain a low oxygen state. The heat sources H′ are controlled to for example make the temperature 600 to 700° C. so as to heat the transported workpieces W′ to the melting point of the brazing material or more. The cooling chamber 104 is provided with a water-cooling type slow cooling chamber 105 and an air-cooling type rapid cooling chamber 106. The brazed workpieces W′ are cooled and taken out from the open part 108.